Option to prevent duplicate connections

rtshell/rtcon.py

@@ -85,6 +85,18 @@ def connect_ports(paths, options, tree=None):
         port_objs.append(port_obj)
 
     conn_name = options.name if options.name else None
+
+    if options.no_duplicates:
+        for p in port_objs:
+            if p.get_connection_by_name(conn_name):
+                raise rts_exceptions.DuplicateConnectionNameError(conn_name,
+                                                                  p.name)
+            if options.id:
+                if p.get_connection_by_id(options.id):
+                    raise rts_exceptions.DuplicateConnectionIDError(options.id)
+        if port_objs[0].get_connections_by_dests(port_objs[1:]):
+            raise rts_exceptions.DuplicateConnectionError(cmd_paths)
+
     port_objs[0].connect(port_objs[1:], name=conn_name, id=options.id,
             props=options.properties)
 
@@ -106,6 +118,8 @@ def property_callback(option, opt, option_value, parser):
 Connect two or more ports.'''
     version = rtshell.RTSH_VERSION
     parser = optparse.OptionParser(usage=usage, version=version)
+    parser.add_option('-d', '--no-duplicates', dest='no_dups',
+            action='store_true', help='Prevent duplicate connections')
     parser.add_option('-i', '--id', dest='id', action='store', type='string',
             default='', help='ID of the connection. [Default: %default]')
     parser.add_option('-n', '--name', dest='name', action='store',
@@ -153,4 +167,3 @@ def property_callback(option, opt, option_value, parser):
 
 
 # vim: tw=79
-

rtshell/rts_exceptions.py

@@ -400,6 +400,37 @@ def __str__(self):
                     self._id)
 
 
+class DuplicateConnectionError(RtShellError):
+    '''An identical connection already exists.'''
+    def __init__(self, ports):
+        self._ports = ports
+
+    def __str__(self):
+        return 'An identical connection already exists between ports {}'.format(
+            self._ports)
+
+
+class DuplicateConnectionIDError(RtShellError):
+    '''A connection with that ID already exists.'''
+    def __init__(self, conn_id):
+        self._conn_id = conn_id
+
+    def __str__(self):
+        return 'A connection with ID {} already exists between the ' \
+                'specified ports'.format(self._conn_id)
+
+
+class DuplicateConnectionNameError(RtShellError):
+    '''A connection with that name already exists.'''
+    def __init__(self, conn_name, port_name):
+        self._conn_name = conn_name
+        self._port_name = port_name
+
+    def __str__(self):
+        return 'A connection with name {} already exists from the ' \
+                'specified port {}'.format(self._conn_name, self._port_name)
+
+
 class BadPortTypeError(RtShellError):
     '''The port type is not defined.'''
     def __init__(self, rtc, port):